Hybrid electrical insulator bushing

Abstract

A bushing for insulating a conductor in a high-voltage electrical transmission system is fabricated of paper and metallic foil disposed as coaxial layers about the conductor. At one end of the bushing, the paper is impregnated with oil. At the opposite end of the bushing, the paper is impregnated with a resin which cures to a solid form. The paper, oil and resin serve as electrical insulators, while the metallic foil serves to disperse uniformly the electric field. A mounting flange is positioned on an enclosing casing for setting the resin end of the bushing into the housing of an electrical apparatus to which the bushing may be mounted so as to prevent contamination of the interior of the housing with the oil.

I claim: 
     
       1. An electrical bushing comprising: a core formed of sheets of electrically conducting material separated by electrically insulating material, said sheets of electrically conducting material being interleaved with and, coaxially disposed with the electrically insulating material;   an insulating casing enclosing an end of said core;   an electrically conducting rod traversing said core, and extending from an end of said core to form a terminal; and wherein   said insulating material includes a cured resin at one end of said core, and an insulating oil at a second end of said core within said casing; said resin being absent from said second end of said core, and said oil being absent from said one end of said core.   
     
     
       2. An electrical bushing comprising: a core formed of sheets of electrically conducting material and sheets of electrically insulating material, said sheets of electrically conducting material being interleaved with and coaxially disposed with said sheets of electrically insulating material;   an insulating casing enclosing an end of said core;   an electrically conducting rod traversing said core, and extending from an end of said core to form a terminal; and wherein   said sheets of insulating material include a cured resin at one end of said core, and an insulating oil at a second end of said core within said casing; said resin being absent from said second end of said core, and said oil being absent from said one end of said core.   
     
     
       3. A bushing according to claim 2 wherein said sheets of electrically conducting material of said core are metallic foils. 
     
     
       4. A bushing according to claim 3 wherein said sheets of electrically insulating material of said core comprise sheets of paper. 
     
     
       5. A bushing according to claim 4 wherein said sheets of paper are impregnated with said resin and said oil. 
     
     
       6. A bushing according to claim 5 further comprising a mounting flange disposed traversely of a longitudinal axis of said bushing, and wherein said oil is disposed to one side of said flange to prevent entry of said oil into an equipment to which said bushing may be mounted by said flange. 
     
     
       7. An electrical bushing comprising: a core constructed of a set of coaxial preformed cylinders of electrically conducting material, said core including electrically insulating material interspersed with said cylinders;   an insulating casing enclosing an end of said core;   an electrically conducting rod traversing said core, and extending from an end of said core to form a terminal; and wherein   said insulating material includes a cured resin at one end of said core, and an insulating oil at a second end of said core within said casing; said resin being absent from said second end of said core, and said oil being absent from said one end of said core.   
     
     
       8. An electrical bushing comprising: a core formed of sheets of electrically insulating material disposed coaxially about an axis of said core, said core including electrically conducting material interleaved with said sheets of insulating material and formed directly onto part of the sheets of insulating material by use of a conducting ink or paint;   an insulating casing enclosing an end of said core;   an electrically conducting rod traversing said core, and extending from an end of said core to form a terminal; and wherein   said sheets of insulating material include a cured resin at one end of said core, and an insulating oil at a second end of said core within said casing; said resin being absent from said second end of said core, and said oil being absent from said one end of said core.   
     
     
       9. A bushing for insulating an electrical conductor comprising: a core formed of sheets of electrically conducting material and sheets of electrically insulating material, said sheets of electrically conducting material being interleaved with and coaxially disposed with said sheets of electrically insulating material, said core being disposed about a conductor;   said sheets of electrically insulating material extending from one end portion of said core to a second end portion of said core; and wherein   said sheets of electrically insulating material in said one end portion are imbedded in a solid insulant, and said sheets of electrically insulating material in said second end portion are immersed in a liquid insulant; said solid insulant being absent from said second end portion, and said liquid insulant being absent from said one end portion.   
     
     
       10. A bushing according to claim 9 wherein said solid insulant is a cured resin, and said liquid insulant is an oil.